The present invention relates to a moving member fixing apparatus which moves a moving member, fixed to and released from a stationary member, in a released state with respect to the stationary member.
As the most typical example of a moving member fixing apparatus of this type, a printing switching apparatus for a sheet-fed offset rotary printing press with a convertible press mechanism is available which can perform both single-sided printing and double-sided printing with one printing press. Such a printing switching apparatus has a drive connecting/disconnecting means for connecting and disconnecting drive connection from an auxiliary motor to a moving cam, and a fixing/releasing means for fixing and releasing the moving cam to and from a stationary cam. In this structure, to adjust the opening/closing timing of the gripper of an impression cylinder, the moving cam in contact with a cam follower that opens and closes the gripper is moved toward the surface of the impression cylinder, to adjust the phase of the moving cam.
A conventional moving member fixing apparatus has a moving cam fixing air cylinder serving as a fixing/releasing means for fixing and releasing a moving cam to and from a stationary cam, an auxiliary motor which moves the moving cam to adjust the phase with respect to the stationary cam, and a gear connecting air cylinder serving as a drive connecting/disconnecting means for transmitting and disconnecting the drive of the auxiliary motor to the moving cam. In this structure, the drive of the auxiliary motor can be transmitted to the moving cam through the gear connecting air cylinder. Then, the moving cam fixing air cylinder releases the moving cam from the stationary cam, and the auxiliary motor is driven, so that the moving cam is switched to a phase for double-sided printing (see Japanese Patent Laid-Open No. 2000-52535).
The conventional moving member fixing apparatus requires two air cylinders, i.e., the moving cam fixing air cylinder serving as the fixing/releasing means for fixing and releasing the moving cam to and from the stationary cam, and the gear connecting air cylinder which transmits or disconnects the drive of the auxiliary motor to the moving cam. Accordingly, not only the number of components increases, but also the apparatus becomes large in size and the structure is complicated.